The olefin metathesis reaction, also known as dismutation and disproportionation of olefins, is a reaction of a great practical interest. The reaction generally involves redistribution of alkylene fragments by the scission of carbon-carbon double bonds in olefins. By catalyzing the reaction, pairs of carbon-carbon bonds can be reorganized in a statistical manner to transform simple molecules into molecules with desirable properties.
Various catalysts have been developed to improve catalytic performance in metathesis reaction.
For example, US 2010/0145126 A2 describes a catalyst containing a transition metal on a support mixed with a co-catalyst containing Group IA, IIA, IIB, or IIIA metal on a support for use in a process of producing olefins by metathesis reaction. The reaction is required to be carried out in the presence of hydrogen, which is an expensive feedstock and requires a lot of cautions to deal with. In addition, the presence of hydrogen induces hydrogenation to occur as a side reaction which leads to poor propylene selectivity.
Moreover, S. Huang et al. (Journal of Molecular Catalysis A: Chemical 226 (2005), 61-68) and H. Liu et al. (Journal of Natural Gas Chemistry 18(2009), 331-336) studied the use of tungsten oxide on alumina-zeolite support for olefin metathesis catalyst and S. Liu et al. (Journal of Natural Gas Chemistry 19 (2010), 482-486) and S. Huang et al. (Applied Catalysis A: General 404(2011), 113-119) studied the use of molybdenum oxide on alumina-zeolite support. They explained that adding zeolite to alumina support increases Brönsted acidity of the catalyst which results in improved conversion and selectivity in metathesis reaction of ethylene and butene to produce propylene. However, these catalysts suffer from rapid deactivation due to accumulation of coke species.